Cryptography with Shrinking Generators Fundamentals and Applications of Keystream Sequence Generators Based on Irregular Decimation

This book offers a broad survey of all information made public - from 1993 until today - on keystream sequence generators based on irregular decimation, which are referred to as shrinking generators. Starting with an overview of cryptography, it describes each type of generator - shrinking, self-shrinking, modified self-shrinking, generalized self-shrinking and the DECIM algorithm - with examples and references. Further, the book discusses several attacks on these generators and applications. It concludes by demonstrating how the output sequences can be modeled by means of different families of one-dimensional cellular automata, rendering the generators vulnerable to attacks. Intended for researchers and graduate students, the book will hopefully inspire them to search for more details on this family of generators and to address the open problems in this field.

Chapter 1- Introduction to stream ciphers.- Chapter 2- Keystream generators based on irregular decimation.- Chapter 3- Modelling through linear cellular automata.- Chapter 4- Cryptanalysis.- References.

Sara D. Cardell received her Ph.D. degree from the University of Alicante, Spain, where she also pursued her postdoctoral studies. During this period, she spent one year working with Dr. Amparo Fúster-Sabater at the Spanish National Research Council (C.S.I.C.). More recently she joined the coding theory research group at the University of Campinas, Brazil. Dr. Cardell has authored a considerable number of publications and has served on the organizing committee of several scientific events and research projects. Her research interests include poset metrics, Fq-linear codes MDS codes, SPC codes, stream ciphers, pseudo-random sequences and cryptanalysis.

Amparo Fúster-Sabater received her B.S. and Ph.D. degrees in physics from Universidad Complutense, Madrid, Spain. Since 1988, she has been with the Spanish National Research Council (C.S.I.C.) at the Department of Information Processing and Cryptography of the Institute of Physical and Information Technologies (ITEFI). Dr. Fúster-Sabater is the author of many articles in reputed international mathematical and engineering sciences journals, conference papers and several books. Her current research interests include cryptanalysis, stream ciphers and pseudo-random sequences.